Side mounted temperature probes for pressware die sets

ABSTRACT

In a temperature controlled segmented die for forming pressed containers such as plates, trays, bowls or the like including a die segment with a forming surface and an outer movable annular die member there is provided a side mounted temperature probe which extends laterally around the movable annular die member and toward the forming surface of the die segment. The apparatus is particularly useful for forming pressed paperboard containers such as paper plates.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/153,096, filed Sep. 9, 1999.

TECHNICAL FIELD

[0002] The present invention relates to the temperature-controlled diesets for forming food serving disposable pressware containers, such asplates, bowls, trays and the like, and more particularly to atemperature controlled die set utilizing a side mounted, flexibletemperature probe which is angled toward the forming surface of a diesegment. The apparatus of the present invention is particularly usefulfor forming plates and the like from paperboard blanks, wheretemperature control near the forming surfaces is particularly important.

BACKGROUND

[0003] Pressed containers, such as pressed paperboard containersincluding plates, trays, bowls and the like are well known in the art.Typically, such articles are manufactured on an inclined die set havingupper and lower halves. Illustrative in this regard is U.S. Pat. No.5,249,946 to Marx assigned to the assignee of the present invention.Referring to the '946 patent, a typical product is manufactured by wayof feeding a continuous paperboard web into a cyclically operatingblanking section. The forming section includes a plurality ofreciprocating upper die halves opposing, in facing relationship, aplurality of lower die halves. The upper die halves are mounted forreciprocating movement in a direction that is oblique or inclined withrespect to the vertical plane. The blanks, after cutting, are gravityfed to the inclined lower die halves in the forming section.

[0004] Particular forming dies and processes for making pressedpaperboard products are likewise well known. Most typically, dies setsfor forming paperboard containers include a male or punch die half and afemale die half. Typically, the punch half is reciprocally mounted withrespect to its opposing die half and both die halves are segmented. Oneor more portions of the die halves may be spring-biased if so desired,and the particular geometry of the die will depend upon the productdesired. In this regard, there is shown in U.S. Pat. No. 4,832,676 toJohns et al. an apparatus for forming a compartmented paperboard plate.The dies illustrated in the '676 patent includes spring-biased segmentsas well as pressure rings on the punch half and draw rings about theopposing plate. The particular apparatus further includes anarticulated, full area knock-out.

[0005] Forming operations can be somewhat critical in order to producequality product at the desired rates. In this respect U.S. Pat. No.4,721,500 to Van Handle et al. is informative. Note also U.S. Pat. No.4,609,140 to Van Handle et al. The '140 patent provides a generaldescription of one known forming method as will be appreciated from FIG.3 thereof. FIG. 3 shows a cross section of the upper die half and lowerdie half which are utilized to press a flat, circular paperboard blankinto the shape of the plate. The construction of the die halves and theequipment on which they are mounted is substantially conventional; forexample, as utilized on presses manufactured by the PeerlessManufacturing Company. To facilitate the holding and shaping of theblank, the die halves are segmented in the manner shown. The lower diehas a circular base portion and a central circular platform which ismounted to be moveable with respect to the base. The platform is camoperated in a conventional manner and urged toward a normal positionsuch that it's flat top forming surface is initially above the formingsurface of the base. The platform is mounted for sliding movement to thebase, with the entire base itself being mounted in a conventional manneron springs. Because the blank is very tightly pressed at the peripheralrim area, moisture in the paperboard which is driven therefrom duringpressing and the heated dies cannot readily escape. To allow the releaseof this moisture, at least one circular groove is provided in thesurface of the base which vents to the atmosphere through a passageway.Similarly, the top die half is segmented into an outer ring portion, abase portion and a central platform having a flat forming surface. Thebase portion has curved, symmetrical forming surfaces and the outer ringhas curved forming surfaces. The central platform in the outer ring areslidingly mounted to the base and biased by springs to their normalposition shown in FIG. 3 in a commercially conventional manner. The topdie half is mounted to reciprocate toward and away from the lower diehalf. In the pressing operation, the blank is first laid upon the flatforming surface, generally underling the bottom wall portion of theplate to be formed, and the forming surface makes first contact with thetop of the blank to hold the blank in place as the forming operationbegins. Further downward movement of the top die half brings thespring-biased forming surfaces of the outer ring into contact with theedges of the blank to begin to shape the edges of the blank over theunderlying surfaces in the areas which will define the overturned rim ofthe finished plate. However, because the ring is spring-biased thepaperboard material in the rim area is not substantially compressed ordistorted by the initial shaping since the force applied by the formingsurfaces is generally light and limited to the spring force applied tothe ring. Eventually, the top die half moves sufficiently far down sothat the platform segments and the ring are fully compressed such thatthe adjacent portions of the forming surfaces are coplanar. In aconventional manner the die halves are heated with electrical resistanceheaters and the temperature of the die halves is controlled to aselected level by monitoring the temperature of the dies withthermistors mounted in the dies as close as possible to the formingsurfaces.

[0006] For paperboard plates stock of conventional thicknesses ie. inthe range of from about 0.010 to about 0.040 inches, the spacing betweenthe upper die surface and the lower die surface decline continuouslyfrom the nominal paperboard thickness at the center to a lower value atthe rim.

[0007] The springs upon which the lower die half is mounted aretypically constructed such that the full stroke of the upper die resultsin a force applied between the dies of from about 6000 to 8000 pounds.

[0008] The paperboard which is formed into the blanks is conventionallyproduced by a wet laid paper making process and is typically availablein the form of a continuous web on a roll. The paperboard stock ispreferred to have a basis weight in the range of from about 100 poundsto about 400 pounds per 3000 square foot ream and a thickness or caliperin the range of from about 0.010 to about 0.040 inches as noted above.Lower basis weights and caliper paperboard is preferred for ease offorming and for saving feedstock costs. Paperboard stock utilized forforming paper plates is typically formed from bleached pulp furnish, andis usually double clay coated on one side. Such paperboard stockcommonly has a moisture (water content) varying from about 4.0 to about8.0 percent by weight.

[0009] The effect of the compressive forces at the rim is greatest whenthe proper moisture conditions are maintained within the paperboard: atleast 8% and less than 12% water by weight, and preferably 9.5 to 10.5%.Paperboard in this range has sufficient moisture to deform underpressure, but not such excessive moisture that water vapor interfereswith the forming operation or that the paperboard is too weak towithstand the high compressive forces applied. To achieve the desiredmoisture levels within the paperboard stock as it comes off the roll,the paperboard is treated by spraying or rolling on a moisteningsolution, primarily water, although other components such as lubricantsmay be added. The moisture content may be monitored with a hand heldcapacitive type moisture meter to verify that the desired moistureconditions are being maintained. It is preferred that the plate stocknot be formed for at least six hours after moistening to allow themoisture within the paperboard to reach equilibrium.

[0010] Because of the intended end use of the paper plates, thepaperboard stock is typically coated on one side with a liquid prooflayer or layers. In addition, for esthetic reasons, the paper platestock is often initially printed before being coated. As an example oftypical coating material, a first layer of polyvinyl acetate emulsionmay be applied over the printed paperboard with a second layer ofnitrocellulose lacquer applied over the first layer. The plate stock ismoistened on the uncoated side after all of the printing and coatingsteps have been completed. In a typical forming operation, the web ofpaperboard stock is fed continuously from a roll through a cutting dieto form the circular blanks which are then fed into position between theupper and lower die halves. The dies halves are heated as describedabove, to aid in the forming process. It has been found that bestresults are obtained if the upper die half and lower diehalf—particularly the surfaces thereof—are maintained at a temperaturein the range of from about 250° F. to about 320° F., and most preferablyat about 300° F.±10° F. These die temperatures have been found tofacilitate the plastic deformation of paperboard in the rim areas if thepaperboard has the preferred moisture levels. At these preferred dietemperatures, the amount of heat applied to the blank is apparentlysufficient to liberate the moisture within the blank under the rim andthereby facilitate the deformation of the fibers without overheating theblank and causing blisters from liberation of steam or scorching theblank material. It is apparent that the amount of heat applied to thepaperboard will vary with the amount of time that the dies dwell in aposition pressing the paperboard together. The preferred dietemperatures are based on the usual dwell times encountered for normalproduction speeds of 40 to 60 pressings a minute, and commensuratelyhigher or lower temperatures in the dies would generally be required forhigher or lower production speeds, respectively.

[0011] As will be appreciated by one of skill in the art, the knock-outsare important for holding the container blank on center during formationand for separating the finished product from the die halves,particularly during high speed operation. The mechanical features can befurther augmented pneumatically as is disclosed in U.S. Pat. No.4,755,128 to Alexander et al. Other patents of interest include: U.S.Pat. No. 4,435,143 to Dempsey; U.S. Pat. No. 5,041,071 to Reasinger etal.; and U.S. Pat. No. 4,778,439 to Alexander.

[0012] A temperature sensor such as a thermocouple, thermistor, or aresistive temperature device (“RTD”) can be inserted externally, that isfrom outside of the die set periphery straight into the die or punchhalf forming base to give a relative temperature measurement. Thissensing method does not provide a realistic measurement of the formingsurface temperature since the sensor is typically several inches away.Wider swings in actual forming surface temperatures can exist with suchan externally mounted temperature sensor due to the time lag resultingfrom the distances between the heating element, the forming surface, andthe sensors. A peripherally mounted temperature sensor can be easilyinstalled or replaced if the die set is hot and mounted in a formingpress, but provides relatively poor forming surface temperature controland consistency. Thus formed, pressware products will have largerdeviations in formation, heat pressing and correspondingstrengths/rigidity. While a peripherally mounted temperature probe is alow cost simple method, it is not preferred due to the lack of controland consistency.

[0013] Another method which is commonly used involves internallyinserting a temperature probe into a segmented die directly above theforming surface in an axial position above the area desired to bemeasured. A temperature sensor such as a thermocouple, thermistor or RTDcan be inserted axially (internally from within the die set towards thedie or punch die surface) to provide improved temperature control andconsistency. The temperature sensor typically is inserted internally toavoid interference with the moving components of the die set including,for example, a pressure and draw ring. Formed pressware products willhave more consistent formation, pleat pressing and correspondingstrength/rigidity. However, the sensor must be installed or replacedwhen the die half is out of the forming press. This is a safety concernwhen the heavy die set is hot it must be handled/lifted out of and intothe press. Excessive machine down time is experienced using thisinternal or axially mounted method. Up to twelve thermocouples in totalcan be used in a typical forming press to provide independenttemperature contrtol for all of the plurality of die and punch halves.The chance of a thermocouple failure are thus substantially increased.All the forming lanes of the press must be shut down to replace onefailed internally mounted thermocouple resulting in significant machinedown time, loss of production and non-productive man hours. Product costincreases and product quality decreases if a failed thermocouple is notreplaced immediately.

SUMMARY OF INVENTION

[0014] This invention relates to the application of a side mountedtemperature sensor such as thermocouples, thermistors, RTD, and the likein matched metal pressware die sets for the conversion of food servicedisposable articles such as plates, bowls, trays, and platters toimprove ease of installation and replacement upon failure of thetemperature sensors. The side mounted temperature sensors are easier toinstall and replace upon failure and result in less machine downtime andless non-productive man hours, thus increasing forming productivity(product output) and reducing product cost while maintaining aconsistent, quality pressed product.

[0015] Accurate temperature measurement is essential in the productionof consistent quality pressed paperboard products such as plates, bowls,oval platters and trays. The moistened paperboard is cut into blanks(which may be scored) and formed between two heated matched metalforming die halves (die and punch) which are closed under pressure for agiven dwell period; typically on the order of 1 second or less. Thepaperboard container in the blank is folded into pleats during theforming and is dried to conform to the shape of the die set. Thecombination of moisture, heat and pressure is necessary to obtain thefinal product shape and to press the paperboard pleats. Final productstrength/rigidity is determined from this process.

[0016] The temperature measurement sensor should ideally be as close aspossible to the forming surface that contacts the paperboard and pressesthe paperboard pleats to maintain consistency and control. Thetemperature measurement sensors must be inserted in a manner such thatthey do not interfere with the moving die set components such as thedraw ring, and pressure ring, and so forth, that are necessary tocontrol paperboard gathering and plate formation.

[0017] The temperature measurement sensors typically connect to acontroller that turns on and off power to heating components (ring,tubular, cast heaters, and so forth) which are internally located in thedie set halves. The controller will heat or cool the die set towards thedesired process set point based on the input from the correspondingtemperature measurement sensors. One temperature measurement sensor andone controller is typically necessary for each die and punch half acrossthe forming press. A forming press may contain up to six die and punchcombinations, thus requiring a total of twelve temperature sensors andtwelve controllers.

[0018] Temperature probes are available in a wide variety of styles,sizes, lengths, wire diameters, wire coverings, and so forth. The sensorstyles would include thermocouples of type J, K, T, E, R & S wirecombinations that have two dissimilar metals in intimate contact todevelop a voltage which depends on the temperature of the junction andthe particular metals used. The following Table correlates ANSI codeswith the material combinations for thermocouples: Materials andPolarities ANSI Code Positive Negative T Cu Constantan E Ni-CrConstantan J Fe Constantan K Ni-Cr Ni-Al R Pt-13% Rh Pt S Pt-10% Rh Pt

[0019] A resistive temperature device or “RTD” may include a wire-woundceramic element, wound with a purity-controlled platinum wire and aregenerally available from sensor suppliers such as Watlow Gordon ofIllinois. So also thermistors and RTD's, which are electrical conductorsthat experience a change in resistance with temperature, may be employedif so desired.

[0020] The preferred side mounted temperature probes used in accordancewith the present invention are a J style (iron/constantan) sheathgrounded junction thermocouple with a spring loaded bayonet stylefitting such as described hereinafter. Particularly preferredtemperature probes may be obtained from Watlow Gordon of Richmond, Ill.,USA under a part no. 10DJSGBO 43A which defines a construction code,10=VAT (variable adjustable thermocouple) with 6 inch spring, sheathdiameter (inches D={fraction (3/16)} inch), calibration J=type J(iron/constantan), lead protection S=fiberglass with stainless steelover braid (24 gauge stranded), junction G=grounded, round tip, sheathlength (inches B=1), lead length=43 inches, termination/optionsA=standard, 2½ inch split leads. A multiplicity of variations on thepreferred type of probe are possible for the side mount thermocouplewithin the spirit and scope of the present invention.

[0021] In accordance with the invention, a temperature sensor such as athermocouple or thermistors can be inserted externally, that is, fromthe sidewall outside of the die set without interfering with any movingdie set components such as the pressure or draw ring and bent around acorner towards the die or punch forming surface to provide improvedtemperature control and consistency. The die set is especially designedto allow space for the temperature sensors to be inserted without anyinterference. This may involve increasing the overall die set height. Ina preferred embodiment, a removable machined housing component ismounted on to the die or punch base to ease the cornering of thethermocouple during insertion or removal. This housing is mounted withtwo socket head cap screws that can be easily and safely removed from ahot die set. Clearance holes are machined through and into the die baseso that the preferred thermocouple and spring overwrap can be easilyinserted without interference. The rounded tip is ideally the only partof the thermocouple probe which touches the die set near the formingsurface. The bayonet fitting must be adjusted/turned such as to providespring compression upon mounting to ensure that the tip is biased intocontact with the die set metal near the forming surface. This method ispreferred since it provides accurate and consistent temperature controlfor the pressware process without the necessity to remove the die set toinstall or replace temperature sensors. The side mounted temperaturesensors can be replaced in a hot die set safely in minutes withoutremoving the die set, resulting in less machine down time, lower costproduction and minimal product cost impact. The side mounted temperaturesensor technique is easily implemented as would be appreciated from thedetailed description hereinafter.

[0022] Described more generally, there is provided by way of the presentinvention in a temperature controlled, segmented die for forming presscontainers such as plates, trays, bowls, and the like, mounted about anaxis of reciprocation and being provided with an outer annular diemember and a die segment with a forming surface, the outer die memberbeing moveable along the axis of reciprocation with respect to the diesegment and the forming surface along a stroke length proximate to theforming surface there is additionally provided a flexible temperatureprobe having a sensor tip inserted laterally into a sidewall of thesegmented die, outside of the stroke length of the annular member. Theflexible temperature probe extends laterally into the segmented die andis angled to extend toward the forming surface such that the sensor tipis within from about ½ to about {fraction (1/32)} inch of the formingsurface of the die segment. Typically the sensor tip is within fromabout {fraction (1/16)} to about ¼ inch of the forming surface; withinabout ⅛ inch of the forming surface being preferred.

[0023] In general the temperature probe can include a thermocouple suchas an iron/constantan thermocouple, a thermistor or RTD. The temperatureprobe preferably includes means for biasing the temperature sensor tiptoward the forming surface such as a spring which is most preferablyaffixed to a retaining member or to the sidewall of the segmented die.

[0024] There is thus provided in another aspect of the present inventiona temperature controlled segmented die half for forming press containerssuch as plates, bowls, trays and the like mounted about an axis ofreciprocation and including: (a) a die segment defining a formingsurface; (b) means for heating said die segment; (c) an outer annulardie assembly moveably mounted along the axis of reciprocation withrespect to the die segment and forming surface along a stroke lengthproximate to the forming surface; (d) a flexible temperature probe witha sensor tip; (e) a temperature controller coupled to said means forheating said base plate and said flexible temperature probe; and (f)means for securing said flexible temperature probe to the segmented diesuch that the flexible temperature probe is inserted laterally into thesidewall of the segmented die outside of the stroke length of the outerannular die member and the flexible temperature probe is angled toextend toward the forming surface of the die segment such that thesensor tip is within from about {fraction (1/32)} to about ¼ inch fromthe forming surface of the die segment.

[0025] Typically the sensor tip of the flexible temperature probe iswithin from about {fraction (1/16)} to about ¼ inch of the formingsurface; within about ⅛ inch of the forming surface of the base platebeing preferred. In a most preferred embodiment a spring annularlysurrounds the flexible temperature probe and is connected to a retainingmember in a form of a slotted cap affixed to both the spring of theflexible temperature probe and wherein the slotted cap is lockinglyengaged to a pair of pins mounted on the temperature controlledsegmented die, that is a typical bayonet fitting as noted above.

[0026] In still yet another aspect of the invention there is provided amethod of forming a pressed container from a container blank comprising:(a) measuring the temperature with a temperature sensor in a segmenteddie maintained about an axis of reciprocation, the die being providedwith an annular outer member and a die segment with a forming surface,the outer annular die member being moveable along the axis ofreciprocation with respect to the base plate and forming surface along astroke length proximate to the forming surface, the temperature sensorbeing disposed on the tip of a flexible temperature probe, insertedlaterally in a sidewall of the segmented die outside of the strokelength of the outer annular die member, the flexible temperature probeextending laterally into the segmented die and being angled to extendtoward the forming surface such that the sensor is within about from ½to about {fraction (1/32)} inch from the forming surface of the diesegment; (b) in response to the measurement of said temperature sensor,controlling temperature of the die segment; and (c) forming thecontainer by contacting the forming surface with the container blank.The container blank may be paperboard, plastic, paperboard/plasticcomposites and so forth such as are for disposable food servingcontainers. Most preferably the container blank is a paperboardcontainer blank having a thickness from about 0.008 to about 0.050inches. Typically the paperboard container blank has a moisture contentof from about 8 to about 12% by weight; with from about 8.5 to about10.5% being particularly preferred. In general it is desirable tomaintain the temperature of the forming surface of the segmented diebetween about 250° F. and 320° F. when forming a paperboard blank;between about 290° F. and 310° F. being particularly preferred.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The invention is described in detail below with reference to thevarious figures, wherein like numerals designate similar parts andwherein:

[0028]FIG. 1 is a schematic diagram illustrating the temperature probeof the present invention inserted to the upper and lower halves of asegmented die set in an open position;

[0029]FIG. 2 is a schematic diagram of the segmented die set of FIG. 1in a closed position illustrating the inventive temperature probeapparatus;

[0030] FIGS. 3(a) and 3(b) are details showing a particularly preferredmethod of connecting a flexible temperature probe in accordance with thepresent invention; and

[0031]FIG. 4 is a detail illustrating a particularly preferred mode ofproviding a mounting cavity and channel for the flexible temperatureprobe of the present invention; and

[0032]FIG. 5 is a block diagram illustrating the connections between atemperature controller, the inventive temperature probes, and theheating coils located in the die segments of the die halves illustratedin FIGS. 1 and 2. The controller circuitry may also include thenecessary relays, switches, fuses and the like typically used for such aheating application.

DETAILED DESCRIPTION

[0033] The invention is described in detail below with reference to thevarious figures which illustrate specific embodiments of the presentinvention. Such description and exemplification is for purposes ofillustration only and in no way limits the spirit and scope of thepresent invention which is set forth in the appended claims. Inasmuch asthe present invention is an improvement to existing pressware die setsand such apparati, the invention will be described with reference to thedifferences between the present invention and existing equipment. Inthis regard, the following United States Patents are illustrative of thestate of the art and known systems:

[0034] U.S. Pat. No. 5,249,946;

[0035] U.S. Pat. No. 4,832,676;

[0036] U.S. Pat. No. 4,721,500;

[0037] U.S. Pat. No. 4,609,140;

[0038] the disclosures of which are hereby incorporated into thisdescription in their entirety by reference.

[0039] Referring now to FIGS. 1 through 5 the invention will now bedescribed with reference to particular embodiments thereof.

[0040] There is shown in FIGS. 1 and 2 a metal pressware die set 10which includes an upper die half (sometimes referred to in the art asthe punch) 12 and a lower die half (sometimes referred to in the art asthe die) 14. Both halves 12, 14 are segmented pressware dies as will beappreciated from the discussion which follows. Die half 12 and die half14 are mounted about an axis of reciprocation 16 in facing relationshipas shown. Die half 12 comprises generally of an upper base plate 18provided with a knock-out 20. There is additionally provided an annularpressure ring 22 as well as heating coils 24. Base plate 18 is providedwith forming surfaces such as surface 26 which is used to form thesidewall of a paperboard pressware product. It is at such surfaces thattemperature control is particularly important as will be appreciated byone of skill in the art. There may also be provided a plurality ofsprings, such as spring 28 can be used to bias the various parts.Typically, between 4 and 8 springs are used to individually bias thevarious parts. Likewise, knock-out 20 may be spring biased if sodesired. It can be appreciated by one skilled in the art that thevarious parts of the segmented die such as pressure ring 22 andknock-out 20 are capable of movement independently of the other parts ofthe segmented die such as plate 18. Pressure ring 22 makes itparticularly difficult to measure directly the temperature at surface 26of base plate 18 unless one utilized an internal temperature probesystem such as that known in the prior art as described hereinabove. Inaccordance with the invention, there is provided an angled flexibletemperature probe 30 that extends from the sidewall in a transversedirection as shown, that is, transverse being substantiallyperpendicular to the axis of reciprocation about which the die ismounted and is angled towards forming surface 26 so that the tip 34 ofthe temperature probe upon which the temperature sensor is located, isin proximity to surface 26. As will be appreciated hereinafter, pressurering 22 reciprocates about a stroke length indicated at 36, such that itis not possible to have a straight probe mounted on the die half 12approach surface 26 in close proximity.

[0041] On the lower half of FIG. 1 there is shown the lower half (die)of a pressware die set which comprises a base plate 38 having a formingsurface 40 as well as a knock-out 42 and a draw ring shown at 44. It isadditionally provided with heating coils in 46 and a plurality ofsprings, such as spring 48 which may be used to bias the particulardesired segment of the die half if so desired. Typically, between 4 and8 springs are used to individually bias the various parts. In accordancewith the present invention there is provided an angled, flexible probe50 extending from the sidewall 52 of the die half toward forming surface40 of base plate 38. Here again due to the fact that draw ring 44 movesover a stroke length 54, it is not possible for a straight temperatureprobe to come into close proximity of forming surface 40 withoutinterfering with the operation of the segmented die. Thus, in accordancewith the present invention there is provided an angled flexibletemperature probe which can be in close proximity, i.e., {fraction(1/32)} to ½ of an inch of the forming surface without the need to gothrough the top or bottom surface of the die half which typically needsto be mounted on a press so that it is not readily accessible during useas noted above.

[0042]FIG. 2 is a diagram showing the die set of FIG. 1 as it wouldappear during the forming step, that is, upon application of pressure toa paperboard blank, for example, where it can be seen that the outerannular rings such as pressure ring 22, and draw ring 44 (outer ringswhich are annular in nature) move from their rest position along thestroke lengths at 54 and 36. It can be seen that the temperature probes30 and 50 are transversely mounted on the sidewall of the die outside ofthe stroke length of both the rings 22 and 44 respectively. It shouldalso be appreciated that it is best to use a probe with a sensor tipsuch as tip 34 and a tip 56 such that the actual temperature sensor isclose to the area desired to be monitored for temperature. Likewise, itis desirable to see that the tip having the sensor is urged into contactwith the surface of the base plate as close as possible to a criticalforming surface such as surfaces 26, 40 during use. The particularlypreferred system for use in connection with the present invention is aspring loaded bayonet type of mounting system wherein spring loaded capssuch as caps 58 and 60 are used to position the flexible temperatureprobes as is better appreciated as shown in FIGS. 3a and 3 b. There isshown in FIG. 3a a slotted cap 58 as lockingly engageable about abayonet fitting 64 which is affixed to a sidewall such as sidewall 32 ofdie half 12. The cap is preferably affixed to a spring 66 as well as thetemperature probe 30 and wire 31 such that the tip of the probe can beurged against the surface of a channel such as channels 68, 70 in FIGS.1 and 2 in order to accurately measure temperature at the desiredlocation.

[0043] It is particularly preferred to utilize a removable platedefining a cavity to install the inventive probe on a segmented die aswill be described in connection with FIG. 4. FIG. 4 shows the sidewallsuch as sidewall 32 of a segmented die of the upper half of a segmenteddie set sometimes referred to as the punch half. There is provided in aparticularly preferred embodiment of the present invention a C-shapedretaining member 72 provided with bolt holes 74, 76 for bolting member72 to sidewall 32 as well as a central cavity 78 through which the probe30 along with a portion of spring 66 may pass. This way channel 68 isreadily available to an operator or technician wishing to thread probe30 down into the base plate of die half 12. It should be noted that amatching cavity 80 in the sidewall of the die half is provided so thatthe channel 60 may be readily fabricated by conventional techniques.

[0044] Turning finally to FIG. 5 it will be appreciated in accordancewith the invention that the temperature is monitored and the temperatureforming surfaces is controlled by conventional techniques. For example,the input from a probe such as from probe 30, is provided to acontroller such as controller 82 which compares the signal with apredetermined value and will provide electrical power as appropriate toheating coils such as heating coils 24 in order to maintain the desiredtemperature at the forming surface.

What is claimed is:
 1. In a temperature controlled, segmented die forforming pressed containers such as plates, trays, bowls or the like,mounted about an axis of reciprocation and being provided with an outerannular die member and a die segment with a forming surface, said outerannular die member being moveable along said axis of reciprocation withrespect to said die segment and forming surface along a stroke lengthproximate to said forming surface; a flexible temperature probe providedwith a sensor tip inserted laterally into a sidewall of said segmenteddie, outside of said stroke length of said annular die member, saidflexible temperature probe extending laterally into said segmented dieand being angled toward said forming surface such that said sensor tipis within from about ½ to about {fraction (1/32)} inch of said formingsurface of said base plate.
 2. The angled flexible temperature probeaccording to claim 1, wherein said sensor tip is within from about{fraction (1/16)} to about ¼ inch of said forming surface of said baseplate.
 3. The angled flexible temperature probe according to claim 2,wherein said sensor tip is within about ⅛ inch of said forming surfaceof said base plate.
 4. The angled flexible temperature probe accordingto claim 1, wherein said temperature probe comprises a thermocouple. 5.The angled flexible temperature probe according to claim 4, wherein saidthermocouple is an iron/constantan thermocouple.
 6. The angled flexibletemperature probe according to claim 1, wherein said temperature probecomprises a thermistor.
 7. The angled flexible temperature probeaccording to claim 1, wherein said temperature probe comprises aresistive temperature device.
 8. The angled flexible temperature probeaccording to claim 1, wherein said probe comprises means for biasingsaid temperature sensor tip toward said forming surface.
 9. The angledflexible temperature probe according to claim 8, wherein said means forbiasing said temperature sensor tip of said probe towards said formingsurface comprises a spring.
 10. The angled flexible temperature probeaccording to claim 9, wherein said spring is affixed to a retainingmember removably secured to the sidewall of said segmented die.
 11. Atemperature controlled segmented die for forming pressed containers suchas plates, bowls, trays, or the like, mounted about an axis ofreciprocation comprising: (a) a die segment defining a forming surface;(b) means for heating said die segment; (c) an outer annular die membermovably mounted along said axis of reciprocation with respect to saiddie segment and forming surface along a stroke length proximate to saidforming surface; (d) a flexible temperature probe with a sensor tip; (e)a temperature controller coupled to said means for heating said baseplate and said flexible temperature probe; and (f) means for securingsaid flexible temperature probe to said segmented die such that saidflexible temperature probe is inserted laterally into the sidewall ofsaid segmented die outside of said stroke length of said outer annulardie member and said flexible temperature probe is angled toward saidforming surface of said base plate such that said sensor tip is withinfrom about {fraction (1/32)} to about ½ inch from said forming surfaceof said base plate.
 12. The temperature controlled segmented dieaccording to claim 11, wherein said sensor tip is within from about{fraction (1/16)} to about ¼ inch of said forming surface of said baseplate.
 13. The temperature controlled segmented die according to claim12, wherein said sensor tip is within about ⅛ inch of said formingsurface of said base plate.
 14. The temperature controlled segmented dieaccording to claim 1 1, wherein said temperature probe comprises athermocouple.
 15. The temperature controlled segmented die according toclaim 14, wherein said thermocouple is an iron/constantan thermocouple.16. The temperature controlled segmented die according to claim 11,wherein said temperature probe comprises a thermistor.
 17. Thetemperature controlled segmented die according to claim 11, wherein saidtemperature probe comprises a resistive temperature device.
 18. Thetemperature controlled segmented die according to claim 11, wherein saidprobe comprises means for biasing said temperature sensor tip towardssaid forming surface.
 19. The temperature controlled segmented dieaccording to claim 18, wherein said means for biasing said temperaturesensor tip of said probe towards said forming surface comprises aspring.
 20. The temperature controlled segmented die according to claim19, wherein said spring is affixed to a retaining member removablysecured to said sidewall of said segmented die.
 21. The temperaturecontrolled segmented die according to claim 20, wherein said springannularly surrounds said flexible temperature probe and said retainingmember comprises a slotted cap affixed to both said spring and saidflexible temperature probe and wherein said slotted cap is lockinglyengaged to a pair of pins mounted on said temperature controlledsegmented die.
 22. A method of forming a press container from acontainer blank comprising: (a) measuring the temperature with atemperature sensor in a segmented die mounted about an axis ofreciprocation, said die being provided with an annular outer member anda die segment with a forming surface, said outer annular die memberbeing moveable along said axis of reciprocation with respect to said diesegment and forming surface along a stroke length proximate to saidforming surface, said temperature sensor being disposed on the tip of aflexible temperature probe inserted laterally in a sidewall of saidsegmented die outside of said stroke length of said outer annular diemember, said flexible temperature probe extending laterally into saidsegmented die and being angled toward said forming surface such thatsaid sensor is within from about ½ to about {fraction (1/32)} inch ofsaid forming surface of said base plate; (b) in response to themeasurements from said temperature sensor, controlling the temperatureof said die segment; and (c) forming said container by contacting saidforming surface with said container blank.
 23. The method according toclaim 22, wherein said container blank is a paperboard container blank.24. The method according to claim 23, wherein said paperboard containerblank has a caliper of from about 0.008 inches to about 0.050 inches.25. The method according to claim 24, wherein said paperboard containerblank has a moisture content of from about 8 to about 12% by weight. 26.The method according to claim 23, wherein the temperature of saidforming surface is maintained between about 250° F. and 350° F.
 27. Themethod according to claim 26, wherein the temperature of said formingsurface is maintained between 290° F. and 310° F.